Electronic systems for bicycles also known as cyclecomputers provide for a display device mountable on the bicycle, for example a liquid crystal display (LCD) to display travel data, like for example current speed, average speed, cadence, travel time, heart rate etc., detected by suitable sensors and/or calculated by a processor. The bicycle electronic systems can also provide for controlling an electromechanical gearshift. In order to select the data displayed and/or to manually change the speed ratio, bicycle electronic systems comprise input means such as levers and/or buttons.
Such bicycle electronic systems provide for use of a power supply unit for the display device and for the electronics, normally consisting of one or more batteries. The batteries used in such systems can be of the disposable type or of the rechargeable type, in the latter case the possibility of accessing the terminals of the batteries being provided, to allow them to be recharged through a battery-charger, possibly removing them from the bicycle.